switch case

Projects Programming
1

I am surprised that a switch without the case is not flagged as an error:

enum					// display modes for "Time lived"; 
{
	TIME_ALL = 0,		// show years, months, days, hours, minutes and seconds;
	DAYS_ONLY,
	HOURS_ONLY,
	MINUTES_ONLY
};

int mode = TIME_ALL;


void setup()
{
}


void loop()
{
  switch (mode)
  {
    TIME_ALL:
      break;

    DAYS_ONLY:
      break;

    HOURS_ONLY:
      break;

    MINUTES_ONLY:
      break;
  }
}
2

I think all switches without an explicit 'default' case have an implicit 'default' case just before the closing brace.

Hmm - the C standard says it differently (6.8.4.2.5):

If no converted case constant expression matches and there is no default label, no part of the switch body is executed.

3

I think you've missed the point - there are no "case"!
In effect, the statement reads something like

switch (x) {
0: break;
1: break;
}
4

I believe those end up as labels as used with 'goto'.

5

Yeap, this is it, they are considered labels (used for goto).
Thanks.

6

Hah!
Correct, in which case, (no pun intended) ignore reply#2

7

I am still wondering if this is correct C or it should be flagged as an error ("missing case").
I just noticed, how weird, that I have no other C compiler on my machine (as I used to years ago).
Does anyone care to test it on Visual C++ for example, see if they treat it differently?
Thanks again.

8

One more observation:

switch (x) {
0: break;
1: break;
}

The code above, which seems equivalent, generates an error.

9

Yes of course. It's ok to have no cases, but it's not ok to begin a label with a digit.

10

have i been typing out case every time for no reason at all... all... the... time...